System and method of carrier current communication



M. MORRISON 25,106

SYSTEM AND METHOD OF CARRIER CURRENT COMMUNICATION Sept. 5, 1933.

3 Sheets-Sheet 1 Filed May 3, 1930 Sept. 5, 1933. MQRRISQN 1,925,106

SYSTEM AND METHOD OF CARRIER CURRENT COMMUNICATION Filed May 5, 1930 s Shets-Sheet 2 Jive/22b MW, l

Sept. 5, 1933. M MORRlSON SYSTEM AND METHOD OF CARRIER CURRENT COMMUNICATION Filed May 3, 1930 3 Sheets-Sheet 5 menial Patented Sept. 5, 1933 UNITED STATES SYSTEM AND METHOD OF CARRIER CURRENT COMMUNICATION Mcntfcrd Morrison, Chicago, 111.

Application May 3, 1930. Serial No. 449,515

7 Claims.

This application is, in part, a part of application Serial Number 421,790 filed January 18, 1930. This invention relates to the class of structures employing unilateral conductivity, and may be embodied in any of the general class of electron devices, and has particular relation to carrier wave communication tubes, including rectifiers, detectors, amplifiers, and various other kindred and related devices.

Among the objects of this invention are: to provide means for causing alternating currents to function in electron discharge circuits in response to their amplitudes, and to their amplitudes only; to provide an electron discharge device with means for controlling the plate current by defiection of the electron stream in addition to control by quantitative variation thereof; to provide an improved rectifier or detector suitable for carrier current communication circuits which will produce a rectified or detected current curve in true relation to the modulation envelope, and various other objects obvious to those skilled in the art to which this invention appertains, upon studying the specification and the claims hereof.

In the prior art electron discharge devices employing cathodes, anodes, and control grids have been constructed with the grid so related to the cathode and anode, that it merely numerically substracts from or adds to the field intensity between the two electrodes in a direction coincident with the field present in the absence of the grid.

In such a structure the action of the control grid is limited to a mere numerical opposition to M the flow of electrons from the cathodes. This structure has characteristics which limit the control action to very simple and narrowly confined devices.

In the present invention there is provided a class of control grids adapted to not only control the anode current by numerical opposition, but in addition thereto by vector relation, making it possible for the control grid to perform functions not heretofore performed directly by multiple I electrode electron discharge devices; and further, allows almost a limitless combination of relations connecting the grid voltage with the anode current.

The applicant is aware that electron discharge r tubes have been made in the prior art utilizing deflecting electrodes, but these deflecting electrodes have been for use in connection with oscillographic work, and in particular, used in connection with point-by-point methods of cathode ray oscillographs, but this is a class of structures different from the invention herein claimed.

The nature of this invention is such that dephased alternating currents are applied to the grid in a manner to control the anode current as a result of the action of the de-phased currents,

vectorially.

In copending application Serial Number 445,593 filed April 19, 1930, treating any number of polyphased fields, and specifically electric fields in the present case, having sinusoidal variation and de-phasing of an angular value, bearing a certain relation to the vector-direction of the fields and to their total number, it has been shown that revolving fields, with a constant amplitude bearing a straight line relation to the amplitudes of the sinusoids representing the said fields, are produced.

By the use of polyphased fields including quar ter phase fields for the excitation of the grids used in the present invention, the control of the anode current by the grid potentials is made to obey other laws beside the instantaneous variations of the applied fields 'of the tubes of the prior art.

Specifically, one of the principal novelties of this invention is the adaptation of the grids thereof polyphase revolving fields, which have a control potential with reference to the filament, proportional to the maximum amplitude of the applied varying alternating potentials, adapting r the invention as a demodulator or as a detector 8 tube.

The applicant does not limit himself to equiphased fields nor to specific spaced relations; and moreover, does not limit himself at all to revolving fields; and the only limitations set up by the applicant are those specified in the claims hereunder. a

An almost endless number of designs of electron discharge devices employing fields operating vectorially in almost limitless combination may be made embodying the invention as claimed hereunder, but in the present embodiment the description will be limited to revolving vector-fields without going into the embodiments involving os- 100 cillating fields, sinusoidally distributed fields with sinusoidal variation in intensity, or those whose trace may execute irregular paths such as compound Lissajous-figures;

Other and further scopes and objects of the d invention will appear during-the progress of reading the following description in connection with the accompanying drawings.

Fig. 1 illustrates partly in elevation,'and partly in section, an electron discharge device utilizing 110 revolving vector-fields as employed in the embodiment herein described, Figs. 2 to 5 inclusive represent collectively an exploded view of certain details of construction employed in the specific embodiment shown in Fig. 1, Fig. 6 is a diagrammatic circuit using certain conventionalities to illustrate the utilization of the device shown in Fig. 1 as a carrier wave communication reception apparatus, and Fig. 7 is a modulated alternating current wave includedfor reference in connection with the description of the operation of the set-up illustrated in Fig. 6.

Referring to Fig. 1, 1 is a hermetically sealed envelope of a conventional form, having a reentrant stem 2, and a press 3 containing lead-in wires 4, 5, 6, '7, 8, 9, and 10.

Upon the stem 2 is mounted a clamp 11 fixed to the stem 2, clamping it to insulating members 12 and 13, into which are fixed rods 14 and 15, which are utilized in supporting the superstructure hereinafter described.

The present embodiment employs four separate grids mounted on four semicircular ring segments 16, 17, 18, and 19, Fig. 1; and shown in exploded views 2 and 3.

Referring to Figs. 2 and 3, semicircular segments 16, 17, 18, and 19 are provided in the drawings for purposes of teaching the invention, with a plurality of pins 20 and 21 forming grids hereinafter described.

. In practice these pins are in reality rolled into a rectangular section, but this construction detail is dispensed with in Figs. 1, 2', and 3 for clearness; although in the diagram 6, the grid is illustrated as having rectangular cross-sections, which will be described in connection with that figure.

The plurality of pins illustrated in Figs. 2 and 3 are arranged in such an order, that the pins shown in 2 and 3 can be intermeshed as illustrated in Fig. 1, and at the same time retain their separated and insulated character. The slots 22 and 23, Figs. 2 and 3, are fixed at right angles when the grids are meshed, so that the inter meshed grids will be arranged and connected as illustrated in the digram Fig. 6.

The lines 16, 17, 18, and 19, being diagrammatic representations of the 16, 1'7, 18, and 19, Figs. 1 and 2. The grid proper being illustrated by the rectangular pins 20 and 21, being the same group of pins as shown in Figs. 2 and 3 with a round section, this difference being already explained.

Referring to Fig. 5, 24 is a hollow cylindrical anode, having a group of ears such as 25 welded to its outer surface, and bent in such a manner as to secure the said anode to a cylindrical ring of insulating material 26, which is set into insulating pillars 27, 28, 29, and 30, thus forming a unit complete as illustrated in Fig. 5 with all parts fixed with reference to each other.

Anode 24 is located around the grid pins 20 and 21 as illustrated in Fig. 1. The reference numerals used in Fig. 5 represent identical parts bearing identical numerals in Figs. 2 to 6 incluslve.

Anode 24 is also shown in Fig. 6 in its diagrammatic position.

In Fig. 4, 31 is a filament, 32 and 33 are supports welded thereto, all of which is shown in its proper location in Figs. 1 and 6 by the proper numerals. Referring to Fig. l, rods 14 and 15 have insulating sleeves 34 and 35 slipped upon them, onto which is a clamp 36 for holding the filament support 33. Rods 14 and 15 are fixed into semicircular segments 13 and 19, forming electrical connection therewith by means of leads 4 and 10, which are welded thereto.

In the semicircular grid segments 16 and 17 are fixed rods 3'7 and 38, onto which are fixed insulating sleeves 39 and 40, having a clamp 41 to hold the filament support 32. Lead-in wire 5 is welded to support 32 as shown, lead-in wire 7 being connected to filament support 33 through clamp 36. Lead-in wire 8 is welded to anode 24. Lead 6 is welded to semicircular segment 16, and lead 9 is welded to semicircular segment 1'7. The corresponding leads of Fig. 6 bear the same numerals as those described for Fig. 1.

Referring to Fig. 6, 41 is the station terminal equipment, its character and design depending upon whether the embodiment of the invention refers to radio communication reception, carrier- Wave wire transmission reception, or some other applicable embodiment such as likeness transmission reception. The scope of the invention includes any form of intelligence transmission irrespective of its specific character; but in the diagram, 41 is illustrated as a radio station terminal equipment for the reception of audible intelligence signals.

41 may be any suitable circuit, which will selectively receive the modulated carrier wave illustrated in Fig. 7, without destroying the essential characteristics thereof, necessary to the proper functioning of the embodiment of this invention. The modulated carrier wave shown in Fig. '7 may be delivered directly to a second unit 42, or it may be heterodyned, since it is immaterial to this invention whether the original modulated carrier wave is utilized, or a modulation of a different frequency, such as that produced by heterodyning, and/or, equivalent processes as will be obvious upon reading the description hereinafter. 42 is an additional stage if and when desired for amplifying or changing the characteristics of the received wave in some or any manner not detrimental to the proper functioning of this invention.

The output terminals of 42 are connected to a phase-splitter 43. The phase-splitter 43 is illus trated diagrammatically in the simplest possible form for the purpose of teaching the use of this invention, and the circuits therein are not given to represent the best operating form thereof.

44 is the primary of a transformer connected to the output terminals of 42 through a capacitator 45, 46 is a primary of a different transformer connected through reactor 47 to the output terminals of 42. This comprises a simple divided circuit, splitting the carrier frequency received from 42, or a heterodyned frequency thereof, into quarter phase alternating current, the amplitude of each phase being substantially equal, and 90 degrees phase difference between the two phases.

The general effect of phase-splitters upon frequencies having not single isolated values but bands of values will be more fully discussed in the description of the operation of the device, hereinafter given.

48 is a secondary of transformer 44, and 49 is a secondary of transformer 46. The mid-points of these secondaries are connected together by lead 50, which is connected through an adjustable biasing potential 51, which is subject to use if and when desired. Lead 50 is further brought over to an adjustable potentiometer 52, connected to battery 53, which supplies filament 31 with heating current. Lead 8 is connected to an anode battery 54, which in turn is connected through a reception circuit translating device illustrated as head-phones 55, and thus to potentiometer 52, completing the circuit in a general conventional manner.

In some cases it will not be practical to allow the primaries and secondaries of phase-splitter 43 to work without shunts, as incidental loading in the circuits requires a stabilizing loading by shunted resistors across the primaries, and/or, the secondaries of the transformer contained therein to stabilize the phase relations thereof, and in the diagram a means of stabilization has been illustrated conventionally by the resistors 56 and 5'7. 7

In the operation of the device, a communication of some form of intelligence is received at the station terminal 4-.1. The form of this communication may have that shown in Fig. 7, which is illustrated as a single audio frequency har monic, represented by the dotted envelope, modulated upon a carrier frequency.

Such a modulated wave form has upon analysis two frequencies in addition to the carrier frequency for each modulation harmonic present, producing the side bands well known to those skilled in the art. However, filter circuits and related apparatus, if properly designed, can be made to react upon a modulated carrier wave having side-bands, for practical purposes in such a way as to pass the modulated carrier wave as though there were only one harmonic present of magnitude of the order of the carrier frequency.

This invention is not limited to the utilization of both side-bands, and may use one or both with or without the carrier wave, as is understood by trigonometric analysis of the modulated wave.

The wave form illustrated in Fig. 7 may be hetercdyned, if and when desired, at unit 42, and delivered in one form or other to phase-splitter 43. The function of phase-splitter i3 is to treat the received modulated wave, in such a manner as to divide it into two modulated waves, having the effective super-audio frequency components thereof degrees out of phase electrically, or such that one of the said super-audio frequency Waves reaches the effective maximum at the same time that the other reaches an effective zero point and vice versa.

While in this embodiment there has been illustrated a wave split into two components, this invention is not limited thereto, but may be split into any number of components, provided they come within the scope of the claims, as be more fully apparent in the description of the operation of the thermionic discharge device proper hereinunder.

In Fig. 6 the phase-splitter is illustrated in its simplest electrical form for the purpose of teaching the invention, and not as a device of practical dimensions, nor in preferred form.

The two split modulated wave forms delivered from 43 are both substantially similar to 7, having the same concurrent envelope but with the zeros and maxima of the carrier wave shifted as above I described. One split wave is delivered from secondary 48, and the other from secondary 49, to the grids of the electron discharge device hereinafter described.

The resistors 56 and 57 are merely illustrated as practical additions sometimes necessary for the stabilization of the split wave-forms under operation in connection with the electron discharge device.

The wave form delivered from 48 in connected 7 to grids 16 and 1'7, which produces'at the center of the grids, and at thespaoe occupied by the filament 31, an electric field at right angles to the circumferential ends ofthe grid segments, identified by slot 22, Fig. 2.

The wave form delivered by secondary 49 is delivered to the grids l8 and 19, which produces an electric field at right angles to the direction of their circumferential ends illustrated by slot 23, Fig. 2. The slots sing at right angles, the electric fields produced by the two grids are also at right angles. The electric fields produced by the two grids are then at right angles and individually proportional to the instantaneous value of the exciting potentials. The resultant electric field produced by the two grids is the ector sum thereof, being the square root of the sum of the squares of the two instantaneous intensities of the said fields.

If one of the split wave-forms is assigned an effective carrier wave form represented'by a sine wave, having an amplitude proportional to the instantaneous value of the modulation envelope, the other split wave form will have an effective carrier wave proportional to a sine wave 90 degrees out of phase with the first said carrier wave, but with an amplitude equal to it. The sine wave having its phase position 90 degrees different from the other wave may be treated as a cosine wave with respect to the first mentioned wave, so that the vector sum of the two said waves in the discharge device is equal to the square root of the sum of the squares of the sines and cosines of the angles. This being numerically equal to 1 leaves the vector sum of the two fields with reference to the cathode of the device, proportional to the amplitude of the modulated wave, and to the amplitude only, so that the combined effects of the four grids in the described electron discharge device act upon the plate current proportional to the amplitudes only of the modulated wave form, producing current in the plate circuits of the device, andin the reception translating device 55, proportional to the envelope of the carrier wave, or, in other words, the modulation wave is produced directly in the plate circuit by application of the modulated alternating current to the grids.

It is obvious to those'skilled in the art that the quantitive output of the device described in Fig. 6 is necessarily greater than the electrical input thereof; and consequently, the described device may act as an amplifier as well. as a detector or demodulator.

Various designs of grids with diiferent spacings and different wire may be resorted to, to produce the effect herein described. Also other and different embodiments be designed to produce the sameresult, and in some cases more effectively, some of which. will be more fully disclosed in further applications for Letters Patent.

Having fully described one embodiment of this invention, the following are the claims thereof:

1. In a communication receiving system in combination, station terminal apparatus for the reception of modulated carrier current intelligence, means for dividing the said modulated current into de-phased currents, and means to demodulate said currents in accordance with the amplitudes thereof, and with the amplitudes thereof only.

2. In a communication receiving system in combination, station terminal apparatus for the reception of modulated carrier current intelligence, means for dividing said modulated current, and de-phasing the divisions'thereof into polyphase currents, and means to demodulate the said divided current in accordance with the vector sum thereof.

3. In a communication receiving system in combination, station terminal apparatus for the reception of modulated carrier current intelligence, means for adapting said current for demodulation by an electric field moving generally at an angle to the lines of force thereof and an electron device having electrodes for producing said moving field.

4. The method of receiving carrier current communications, which comprises receiving a modulated carrier current, dividing the said current, de-phasing it, and demodulating said current in accordance with the maximum values of the carrier wave, and in accordance with the maximum values thereof only.

5. The method of receiving carrier current communications, which comprises receiving a modulated carrier current wave, dividing the current due thereto, de-phasing it, rectifying said de-phased currents in accordance with the vector sum of the amplitudes thereof.

6. The method of carrier current demodulation which comprises adapting modulated carrier currents to produce an electric field moving generally at an angle to the lines of force thereof, and utilizing said electric field in the demodulation of said currents.

'7. In a carrier wave communication receiving system, station terminal apparatus for receiving modulated carrier current intelligence, means for dividing and de-phasing said currents and delivering same to an electron discharge apparatus, having grids to control the anode current of said device in accordance with the vector sum of the said divided and de-phased currents.

MONTFORD MORRISON. 

